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(No Model.) 2 Sheets-Sheet 1.

P. WILD.

FURNACE.

N0. 393 409. Patented Nov. 27, 1888.

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WITNESSES.

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2 Sheets-Sheet 2.

(No Model.)

P. WILD.

FURNACE.

No. 393,409. Patented Nov. 27, 1888.

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BY I

ATTORNEY WITNESSES.

n Phnlu Lifl vognpher. Washington. ac.

UNITED rATEs PATENT rates,

FRED \VILD, OF DENVER, COLORADO.

FURNACE.

SPECIFICATION forming part of Letters Fatent No. 393,409, dated November27, 1888.

Application filed July 9, 1888.

To aZZ whom it may concern.-

Be it known that I, FRED WILD, a citizen of the United States ofAmerica, residing at Denver, in the county of Arapahoe and State ofColorado, have invented certain new and useful Improvements in Furnacesfor Boilers, of which the following is a specification, reference beinghad therein to the accompanying drawings.

My invention relates to an improved con struction ofboiler-furnaces; anditsobjects are to so arrange and construct the furnace as to insure thedelivery back of the lire-box proper of a sufficient and regulablequantity of air to effect the complete oxidation and combustion of suchcarbonaceous matter as may have escaped from the firebox orcombustion-chamber proper without being properly oxidized forcombustion, in order that the smoke otherwise escaping may be largely,if not entirely, consumedwithin the furnace, the heat of its carbonutilized and the waste of fuel avoided, means simple in construction,easily applied and arranged, and reliable in operation; to which ends itconsists in the features, combinations, and arrangements moreparticularly hereinafter described and claimed.

In the drawings is illustrated an embodiment of my invention, in whichdrawings- Figure 1 is a side view of a furnace with such improvementsadded thereto, part of the side wall being removed; Fig. 2, a transversevertical section thereof on line 00 00, Fig. 1; Fig. 3, a plan View ofthe bridge-plate; Fig. 4, a plan view of the under side of theair-distributer; Fig. 5, a plan view of the air-inlet-regulatingapparatus; Fig. 6, an end view thereof.

In these figures the reference-numerals l 1 indicate the walls of thefurnace, within which is the fire-box or combustion-chamber 2 in thegrate 3, constructed in the usual manner or in any preferred manner.

At the rear of the fire-box or combustionchamber 3 is the bridge4,extending up from a foundation to within a suitable distance of theboiler. This bridge 4 is constructed with the hollow or chamber 5extending across within the bridge the width of the fire-box 2. It maybe provided at one end with the door 18, so that its interior may bereached for the purpose of cleaning. The top of this chamber Serial No.279,466. (No model.)

around, is a short line or passage, 9, closed at its tops, butcommunicating on either side with horizontally-extending dues orpassages 1O 1O, closed at their ends, but each having a number ofapertures, 11 11, on their under sides. The flue or passage 9 and thesewings or extensions having the flues or passages 10 10 should be made offire-clay or other suitable refractory material to enable them to withstand the heat; or, if not made themselves of 0 such refractorymaterial, they should be coated with a good refractory cement or fettle.

The wings 10 are preferably somewhat curved, as shown, and theirouterends may be supported in the walls 1, or by brackets projectingtherefrom, or by supports rising from the base or from the top of thebridge, and they should be so arranged relatively tothe bottom of theboiler 21 that all the products of combustion from the fire-box 2 shallpass through the passages 20 left between the top of the bridge 4 andthe bottom of the wingpassages 10 10.

Contiguous to the stack or chimney 22 is arranged a chamber, 12, theinlet to which is through the register or valved opening 13. From it apassage, 14, leads downward into a chamber, 15, whence a passage, 16,leads upwardly a sufficient distance, then uniting with a seconddownward passage, 17, which at its lower end has an outlet into thechamber 5 within the bridge. These passages from the first chamber 12 tothe chamber 5 may be formed as flues directly within and of the materialof the walls, or they may be pipes embedded therein or pipes supportedthereby or supported independently thereof, and there may be a setthereof on either side of the furnace; or only a single set may be used.Thus arranged a large supply of air is constantly passing through 12,(so long as its register or Valve 13 is open,) thence cia14,16,

and 17 to the chamber 5, whenceit issues both above and below theproducts of combustion, passing over the bridge through the passages 20above by the apertures 11, and below by the apertures 7. The properamount of oxygen is thus supplied to the products of combustion and atthe point and while they are at an exceedingly high temperature, toinsure their proper oxidation and combustion. If the passages be builtwithin the walls of the furnace or within the furnace, the air supplyingthis oxygen is delivered to the products in a highly-heated state, sothat all the conditions for perfect combustion and for the prevention ofsmoke are present.

There is danger, usually, with hot-air passages that somcsoot, dust,ashes, (110., may find passage thcreinto, either from the inlets oroutlets thereof, or through cracks in the walls of the passages orilues, and this to such an extent as to materially impair the usefulnessthereof, especially if more straight or hori zontal passages be providedin which such foreign matters may accumulate. Danger therefrom, however,is prevented in this invention by the peculiar arrangement of theair-passages. As they return upon each other,somewhat after the styleofan ordinary S drain-trap, they do form a trap for foreign matters inthe chamber 15, any foreign matters getting access into the lines orpassages lodging therein, whence they may readily be removed through thedoor or opening thereof. Moreover, from the peculiar shape of the wingsor fluepas sages 1O 10, they being curved or arched, as shown, if anycracks should appear therein, the arched form would cause the edgesofsuch cracks to be pressed firmly together, preventing largely, if notentirely, the ingress therein of foreign matters and the egress of theair.

It is known that air expands largely as it is heated, and that, as aconsequence, the higher it is heated the less the amount (by weight)that passes through a flue of a given area in cross-section; hence asthe fines and the air therein become warmer and warmer the less theamount of air (by weight) that is supplied by the dues at the bridge. Asa matter of fact, however, the greater amount (by weight) should then besupplied, for the fiercer and hotter the fire the greater the quantityof products needing oxygenation. If then the inlet to the dues orair-passages be proportioned to invariably supply the greatest amountneeded, which is when the combustion or fire in the fire-box is at itsattainable maximum, too great a volume will be supplied when the fire iscomparatively low-as, for instance, when just started-and thisvolumcwill be deliveredat the bridge in a cool or comparatively coolcondition, and not in a proper condition for thorough union with anddesired effect on such products; hence at such times there would becreated the very thing intended to be avoided--viz., a volume ofunconsumed products forming smoke. Therefore in this inventionthermostatic devices are also air-- ranged and connected with theinlet-valve, register, or damper 13, to open the latter the wider as theheat increases, or vice versa, so regulating the area of the inletaccording to the demands thereon. This may be done by arranging a tubeor pipe, 23, within the stack 22, such tube containing mercury or othersuitable thermostatic fluid to be acted on by the heat of the productspassing through the stack. Such tube passes around the entire or almostentire inner periphery of the stack, and thence passes out of the stackand is bent to form an almost entire circle, 30, or is attached to atube so formed, after the fashion of the well-known steam-gage, itsouter closed end being at 25.

An arm or red, 27, is pivoted or secured at one end to the closed end 25of the curved tube 30, while its other end is pivoted to a pinion-wheelor to a scg ment thereof, or curved rack 28, whose teeth mesh with thoseof a pinion, 29, upon or connected to the spindle or rod 26 of thevalve, register, or damper 13, journaled in any suitable manner, itbeing herein shown asjournaled near its outer end in a support, 3 in thechamber 12, and also in the walls of the stack 22, and so arranged thatwhen they are in normal condition and the furnace cool the valve orregister is closed. As the furnace becomes heated, the stack becomescorrespondingly hcated by the passage therethrough of the products ofcombustion, causing expansion of mercury, and consequent pressure upontheinterior of the tube 30. In accordance with the known law that acurved tube tends to straighten itself under internal pressure, the tube30 tends to straighten itself, the movement to whichend being of courseat the free end 25. Such movement is in accordance with the heating ofthe mercury in the tube, and is communicated proportionately to thevalve or register by means of the arm 27 and gearing 28 29. Thus as thefire in creases in the fire box and more air is needed for the productsof combustion the inlet is opened proportionately.

To aid in the combustion and conversion of the products of combustion, ajet or quantity of steam may also be admitted to the chamber 5 in thebridge 4, to issue thence with the air. To this end a pipe, 31, leadsfrom any convenient part of the boiler 21 to the chamber, being soarranged that a valve, 32, therein may be connected,either by the arm orred 27 or by an extension thereof, or by an independent rod, to the end25 of the thermostat 23, and so that it is opened by the movement of thelatter under internal pressure, so that when the furnace is very hotsteam may be admitted thereinto, but when the heat is low thatthe steamshall be cut oil by the closing of the valve 32.

exits at the bridge to give sufficient space for theconstantly-increasing volume of the air as it becomes more and moreheated.

Having thus described my invention, what I claim is- 1. A boilerfurnacehaving a hollow bridge, air-passages starting from about the top of thefront of the boiler and leading in the shape of an inverted N to thebridge, a hollow post or pillar centrally located on and communicatingwith the interior of the bridge, and air flues or passages located abovethe bridge and below the boiler, perforated on their under sides andcentrally supportedbythe hollow post or pillar, substantially as setforth.

2. A boiler-furnace having a hollow bridge, an air passage or fluestarting from about the top of the boiler and leading into the bridge, avalve, register, or damper therefor, a thermostatic tube or devicewithin the stack and around near the inside of the wall thereof andconnected on the outside of the stack to a tube bent in circular orpartly hoop form, and a mechanical connection from such latter circularbent tube to the valve, damper, or register, substantially as set forth.

3. The combination of a hollowbridge having apertures to permit theescape of air or steam therefrom into the furnace, a'steam-pipe leadingthereinto from the boiler, a valve in such pipe, a thermostaticdevice inthe stack or chimney, and a connection therefrom to the steam-valve,substantially as set forth.

t. The combination of a hollow bridge perforated and provided with meanspermitting the escape of air or steam therefrom, airflues starting fromnear the top of the front of the boiler and leading in inverted-N shapethereinto, a valve, register, or damper at the inlet of such flues, athermostatic device in the stack, and a connection therefrom to thevalve, register, or damper, substantially as set forth.

5. The combination of a hollow bridge provided with means permitting theescape of air and steam therefrom into the furnace, airflues leadingthereinto, a valve controlling the passage of air therethrough, a pipeleading from the boiler into the hollow bridge, a valve in such pipe, athermostatic device in the stack, and connections therefrom to bothvalves, substantially as set forth.

6. A boiler-furnace having a hollow bridge, permitting the escape of airtherefrom into the furnace, and air dues or passages for supplying airthereto arranged in a zigzag or trap fashion and gradually increasing inthe area of cross-seetion from inlet to outlet, substantially as setforth.

7. A boiler-furnace having a hollow bridge, air passages or fluesleading thereinto, a valve, register, or damper controlling the inlet tothe passages or fines, a thermostatic tube lo FRED \VI lil).

\Vitnesses:

Z. F. VVILBER, B. L. PoLLooK.

